This disclosure generally relates to systems and methods for tracking the locations of a movable target object (e.g., a crawler vehicle or other electro-mechanical machine that is guided by a computer program) as it moves relative to a workpiece or part.
Applications involving manufacturing processes that use crawler vehicles or other computer-controlled electro-mechanical machines often employ location tracking in a reference coordinate system. Existing location tracking solutions fit into two categories: absolute motion tracking and incremental motion tracking. Absolute motion tracking refers to tracking of position and/or orientation defined in a reference coordinate system, such as an airplane coordinate system. Known techniques for absolute motion tracking include optical motion capture, laser tracking, depth cameras, magnetic tracking, and sonic-based tracking.
Incremental motion tracking measures displacements relative to a prior coordinate measurement. One known technique for incremental motion tracking employs encoders which output pulses in response to incremental movements. In applications that use incremental motion measurement, errors can build up over time. Such error build-up is undesirable in use cases requiring finite error with respect to an absolute coordinate system. There is a need to implement a process that provides accurate, absolute measurement at lower update rates that can be integrated into an incremental motion measurement system running at higher update rates.
Although other absolute measurement systems exist to measure position and orientation using optical or image-based techniques, they usually require multiple cameras placed around the target object. One known absolute measurement system that uses a single “depth” camera has limited range and limited ability to distinguish specific features. It would be advantageous to be able to track position and orientation using a single standard video camera.